The Gates campaign comes after Labeaume lost a seven-year legal battle in October. The courts sided with CN who argued that paying for more than maintenance on the bridge would be "detrimental to our shareholders' interest." CN says that the rust on the bridge poses no safety threat, reports Dougherty.

So now the mayor has moved on to another tactic. He's now pressuring investors directly, starting with Gates, though he also says he plans to meet with other, institutional investors.

He even went so far as to suggest that at the start of next year, he could try a campaign involving shorting CN shares until the company steps up.

"He [Bill Gates] could easily lose $100 million on the capitalization of CN," the mayor told Dougherty. "It's not complicated. I know how to do it."

The bridge was built in the early 1900's and nearly 90 people died during its construction. It was inaugurated in 1919 by the Prince of Wales and is considered by Labeaume to be a national treasure akin to the Eiffel Tower or Statue of Liberty.

While the tactic is creative, Gates actually doesn't actually manage most of his investments himself. He leaves that to his business manager, Michael Larson.